This invention relates to apparatus for aligning abutting pipes and more particularly to such apparatus which is adapted to accurately align the inside surfaces of pipe-like members, such as pipes, fittings and the like, for the purpose of making open butt welds and the like. Throughout the specification and claims, the use of the word "pipe" is intended to include pipes, fittings and similar tubular members.
Heretofore in the art to which my invention relates, difficulties have been encountered in aligning the internal surfaces of abutting pipes with the necessary accuracy required in the installation of pipes, fittings and the like in certain installations, such as in nuclear plants and the like. That is, before making open butt welds in such installations, the abutting pipes must be accurately aligned to meet very strict specifications. Accordingly, where open butt welds are made in such installations without properly aligning the abutting pipes, not only is there a great loss in the replacement of expensive stainless steel pipe sections but there is also a considerable loss in the man hours required to replace such improperly installed pipes and fittings.
While various types of internal pipe alignment clamps have been proposed, such clamps have embodied complicated and expensive mechanisms which are very difficult to insert into and remove from the abutting pipe sections being joined by welding. For example, the Looney U.S. Pat. No. 3,633,813 discloses an internal pipe line-up clamp which includes complicated mechanisms for aligning adjacent sections of pipe. Also, the Adams et al. U.S. Pat. No. 3,615,413 and the Jacobsen U.S. Pat. No. 3,330,021 both disclose internal pipe aligning tools wherein scissors-lke elements are employed to align the inner surfaces of adjacent pipes. Such prior art tools for aligning pipes are not only complicated in structure and expensive to manufacture but they are also difficult to insert into and remove from the pipes being aligned.